The main emphasis of the proposed research project concerns the identification, quantitation, and purification of the enzyme components of secretory granules from mast cells and the characterization of their role(s) in mast cell-mediated reactions. Mast cells from rat serosal surfaces, which can be obtained in greatest abundance and purity, and from human pulmonary tissue, which are of greatest relevance, will be utilized. Specific aims with rat mast cells include the subcellular localization, purification and characteization of carboxypeptidase A; effect of chymase on mast cell degranulation and of chymase and carboxypeptidase A on biologic substrates; and the definition and isolation of secretory and putative nonsecretory mast cell cytoplasmic granules. Projects with human mast cells include definition of conditions to improve the yield and purity of mast cells extracted from human lung; purification to homogeneity, structural characterization and analysis of kinetics and substrate specificity of mast cell tryptase; and production of monospecific and monoclonal antibodies to purified tryptase. Recognition of the role of mast cells in subacute and delayed forms of inflammation, indicates a biologic role for mediators other than histamine in the modulation of such an inflammatory response. Definition of and detection methods for those enzymes released from mast cells may provide specific and sensitive markers of mast cell involvement in human disease, which in turn may assist in the diagnosis and treatment of allergic disease and in understanding of the role of this cell type in health as well as in disease.